Electric flour sifter



Marcha, 1942. A. @.wlLcox 2,274,914

ELECTRIC FLOUR -sIFTER Filed July l2, 1940 2 Sheets-Sheet l l ff /l l 40 f 49455 54 w /0 unl '1 1 vl 3,? 476' 46g; of 57 a@ 5.9 lll ,3J 74 ,e6 l 6.// 7, 4.9 'e5 f7 j; l 41j .0 a, 6.9

i292@ /m W A. C. WILCOX ELECTRIC FLOUR SIFTER Y March 3, 1942.

. Filed July l2, 1940 2 Sheets-Sheet 2 Patented Mar. 3, 1942 UNITED STATES PATENT OFFICE- z,z14,s14

Emc'rarc nous snrrsa Albert c. Wilcox,- Em uverpwl, omo Appunti July 12, 1m, semi Nn. 345.110

(ci. soa-347) t 5Claims.

The invention relates to our sii'ters and more particularly to a sifter having a reciprocating sieve or screen operated by an electromagnet.

An object of the invention is to provide an electric our sifter having a vertically disposed electromagnet centrally located within the shell of the sitter, the vertically reciprocating core oi' the magnet having its lower end centrally supporting a sieve or screen in the lower portion of the shell and adapted to rapidly vibrate the same A further object is to provide an electric iiour sifter of this type in which a make-and-break device is automatically operated by the reciprocating core oi' thellmagnet.

A still further object is to provide a flour sitter A of this type in which an armature carried by the Another object is to provide such a flour sifter in which the periphery ci the sieve or screen strikes a positive stop at the end of its upward movement.

Still another object of the invention is to provide anelectric flour sitter in which a ilexible rubber diaphragm is connected to the reciprocating core of the magnet and sealed to the lower end of the shell or housing enclosing the magnet,

The above objects together with others which will be apparent from the drawings and following description or which may be later referred to, may be attained by constructing the improved electric flour sifter in the manner illustrated in the accompanying drawings in which Figure i is a vertical sectional view through an electric cur sifter embodying the invention;

Fig. 2, a fragmentary vertical sectional view through a modified form of electromagnet;

Fig. 3, a fragmentary sectional view through the upper portion of the electromagnet showing a modified fcrm of make-and-break;

Fig. 4, a top plan view of the improved fiour sifter with the cap removed from the magnet housing or shell; and

Fig. 5, a plan view of the sieve or screen.

Similar numerals rei'er to similar parts throughout the several views. I

The improved flour sitter includes a substantially cylindric vertical shell I0 which may be formed of sheet metal or other suitable material preferably provided with an outwardly disposed peripheral bead or rib II near its upper end and an inwardly disposed' bead or rib I2 at a point y spaced below the bead I I.

The upper end of the shell I0 may be cut ot! at an angle as in usual practice and provided with Iii the rim bead I3 and the lower end ot the shell may be provided with the u sual rim bead I4.

A funnel shapedinner shell I5 is provided at its upper end with the outturned peripheral ilange Il which rests upon the inwardly disposed rib or bead I2 in the shell III.

Below the funnel shaped shell I5 is located a metal ring I1 which may be connected to the shell III as by rivets Il.

This ring is in the form of a spider, having a plurality oi' radially disposed arms or spokes I9 to the inner ends of which is formed a ring 20 for supporting the magnet which operates the sieve The outer shell or housing 2I, for the magnet.v may be formed of aluminum or other sheet metal and ts snugly within the ring 20 having at its lower end the outturned peripheral flange 22 fltting against the underside of the ring 20 and terminating in the downturned annular flange 23.

The cap 2l may be provided upon the upper end oi' the magnet housing or shell 2 I.

The magnet includes the U=shaped iield piece 25 formed o! soit iron and connected to the` magnet housing or shell 2i as by Screws 26.

The magnet coil 21 is mounted within the field piece 25 by means of thev central tubular shell 28 preferably formed of brass and having an outturned dang@ 2s at its lower end engaging the lower end ci the coil andan inturned flange 3B at its upper'end which is held in engagement with the top of the ileld piece 25 as by the hollow threaded stud il i An insuiaticn biock t2 is xed upon the top of the i'leld piece 25 as by the screw 33 and has mounted on one end as by the binding screw 34, a fixed contact 3% connected as by said binding screw to one wire 3S of the electric circuit.

A spring Contact arm 38 is connected to the other side of the insulation block 32 as by the binding screw 34 which also connects said spring contact arm to the wire 3l.

The movable contact 38 upon the free end of the spring arm 3l is adapted to contact with the fixed contact 35.

A soft iron core 39 is mounted for vertical reciprocation within the brass tube 28 of the magnet coil and is provided at its upper end with a finger 4I) having an insulation point 4I adapted to strike the `spring contact arm 31 and raise the same to break the contact at 3835 on each up-stroke of the core 39.

The lower end of the soft iron core 33 is provided with a threaded bore 42 which receives the upper threaded end 43 of a double ended der 45v on the stud being The armature 'l1 is attached to the lower end of the core 35 by means of this stud, the shoullocated beneath the amature. f

This amature is so located that on the up'- stroke of the core the ends of the amature will strike the lower ends of the field piece 25.

To limit the downward movement of the core,

the one end of the armature may be provided with a notch I8 to accommodate the stop screw 45, the amature striking the head of said screw limiting the downward movement thereof.

The core and armature are assembled to the magnet by means of a ilexible rubber diaphragm 55 having a central opening 5| which receives the lower threaded end 52 of the double ended threaded stud I4.

A stud 53 having a threaded bore 54 in its upper end receives the threaded portion 52` of the stud M andclamps the rubber diaphragm 55 between the shoulder I and the stud 53.

I'he periphery of the flexible diaphragm 50 is sealed within a channel shaped ring 55 which is held clamped against the flange 22 of the magnet housing by means of the clamping clips 55 mounted in spaced relation beneath the arms or spokesl I5 by the screws 51 and extension b1ocks51.

This rubber diaphragm 55 thus supports the core 35 and assembled parts relative to the magnet, and lends itself to easy adjustment to compensate for any movement or length of stroke that may berequired. v

The diaphragm also acts as a seal to completely seal the magnet housing and prevent the fine flour from sifting into the magnet and getting into any of the mechanical parts of the device.

'I'he sieve or screen comprises a channel shaped metal ring 55 having the radial arms or spokes 59 with a hub portion 55 formed at the center to receive the reduced portion 5I of the stud 53.

A thumb screw 62 may be provided upon the threaded extension 53 of the stud 53 for clamping the sieve and the leaf spring 54 thereon.

A wire screen 55 of suitable mesh is carried by the ring frame 58, the periphery of the wire being clamped within thechannel of said-ring.

The outer ends of the leaf spring 5I are engaged under the lower rim bead I4 of the shifter shell so that the core and sieve assembly is normally urged tothe lower position as shown in Figure 1.

The sieve may be so mounted that on the upstroke of the core the ring 58 of the sieve will strike the ring i1.

The handle 55 may be of Bakelite or other suitable insulation material and` is provided with a passage 51 running horizontally through its lower portion and communicating with the vertical passage 58.

The opening 58 through the inside of the handle and through the shell I0 permits the wires 35 and 31 to pass from the magnet into the passage 58 and thence to the passage 51.

An opening may be formed in the lower side of the passage 51 to pemit the wires to be connected after which a plate 1I of metal or the like may be. attached over said opening by any suitable means.

'I'he manner of connecting' the wires is shown inA Fig. 1 in which the wire 35 from the magnet is connected adjacent to the opening 1I to one of the lead wires 12 which enter the outer'end o'f 2,274,9144 threaded stud 44 provided with spaced shouldersy the passage 51 through the usual ilexible cord 13 which may be provided with the conventional attaching plug for connection to a base receptacle or socket.

'I'he wir 31 is connected adjacent to the opening 15 in the handle to a wire 1l leading up through the passage 53 to the push button switch 15, a wire 15 leading from said switch down through the passage 58 and through the passage 51 to a point adjacent the opening 10 where it is connected to the other lead wire 11.

In the operation of the improved ilour sifter the desired amount of flour is placed within' the shell I0, the tapered conical shell i5 holding the bulk of the weight of the flour so that it will not rest upon the sieve, thus, not overt-airing the magnet.

'I'he ilour sifts down between the lower end of the conical shell I5 and the magnet housing 2| onto the screen.

When the switch button 15 is depressed, the magnet is energized quickly pulling the core 35 upward. As the core reaches its upper limit the insulation point 4I thereon strikes the spring contact arm 33 breaking the contact.

The ends of the armature 41 strike the lower ends of the ileld piece 25 and the sieve ring 58 strikes the lower edge of the ring I1 and as the magnet is de-energized by breaking of the circuit the spring 5I quickly throws the core, armature and sieve assembly down to the normal position shown in Fig. 1 at which time the spring contact arm 38 again makes contact.

This operation continues rapidly vibrating the sieve so as to sift the flour therethrough. 'f

Thestroke can be lengthened or shortened by changing the distance between the lower end oi the field piece 25 and the head of the stop screw 49 and also by changing the thickness and flexibility of the vspring contact strip 38.

In Fig. 2 is shown a slight modification in which the make-and-break in the circuit is eliminated, the wires 35a and 31a being connected directly to the magnet and the spring strip 38a, be-

ing provided merely to be struck by the insulation point 4|v upon the upper stroke of the core 39.

This construction gives fairly good results, but is not completely satisfactory for use with the hard type flour which is milled many times finer than the ordinary ilour. This is for the reason that there is not enough throw to the armature to properly work with this hard type flour which has a tendency to cake rather than to sift through the sieve if not thrown up quite a distance oli of the sieve with each vibration thereof.

In Fig. 3 is shown a modification of the makeand-break device in which the spring arm 38h has a curved end 38e adapted to wipe against the curved end 35e of the contact 35h.

The reason for this curved, wiping arrangement of make-and-break device will be obvious, as by having a wiping or scraping action between the contacts will keep the contacting surfaces clean and smooth, and will prevent the fouling of the contacts which is an objection to many forms of make-and-break devices.

Otherwise, the construction and operation is the same as above described.

I claim:

1. An electric flour sifter including a shell open at its lower end, a magnet supported within said shell, a housing enclosing the sides and top of the magnet, a flexible diaphragm connected at its periphery to the lower end of said housing, a vertically reciprocating core within the magnet a normally closed make and break device forj controlling the magnet, means upon the core for opening the make and break device on the upstroke of thecore and a leaf spring ,onnected at its center to the sieve and ihavlng its endsengaged beneath the bottom of the shell for urging the core downward.

2. An electric `flour sifter including a shell open Y at its lower end, a magnet supported within said shell, a housing enclosing the sidesland top of the magnet, a flexible diaphragm connected at its periphery to the lower end of said housing, a vertically reciprocating core withinthe magnet said core being located through and connected to the central portion of said diaphragm, a sieve suspended from the core below the diaphragm, a

spring arm above the magnet in the path of the reciprocating core, a normally closed electric make-and-break device operated by said spring arm for controlling the magnet, means upon the core for engaging the spring arm for opening the make and break device on the up-stroke of the core and a. leaf spring connected at its center to the sieve and having its ends engaged beneath the bottom of the shell for urging the core down- Ward.

3. An electric flour sifter including a shell open at its lower end, a magnet supported centrally within said shell, a housing enclosing the sides and top of the magnet, a flexible diaphragm con--Y nected at its periphery to the lower end of said housing, a vertically reciprocating core within the magnet said core being located through and connected centrally to said diaphragm, a sieve suspended centrally from the core below the diaphragm, means for de-energizing the magnet on the up-stroke of the core and a leaf lspring connected' at its center to the sieve and havingits ends' engaged beneath the bottom of the shell for urging the core downward.

4. An electric flour sifter including a shell open at its lower end, a magnet supported Within said shell, a pole piece in the magnet, a vertically reciprocating core within the magnet, an armature carried by the core and arranged to contact the pole piece on the up-strcke, a stop suspended from the magnet for contact with the armature on the down stroke, a sieve suspended from the core within the lower end of the shell, a spring arm above the magnet in the path of the core, a normally closed make-and-break device operated by the spring arm for controlling the magnet, a finger on the core for contactwith the spring arm for opening the make and break device on the up-stroke of the core and a leaf spring connected at its center to the sieve and having its ends engaged under the bottom of the shell for normally urging the armature against said stop.

5. An electric flour sifter including a shell open at its lower end, a magnet supported within said shell, a housing enclosing the top and sides of the magnet, a pole piece in the magnet, a ver- `tlcally reciprocating core within the magnet, a

flexible diaphragm connected at its periphery to the bottom of the magnet housing the core being located through and centrally connected to said diaphragm, an armature carried by the core and arranged to contact the pole piece on the upstroke, a stop suspended from the magnet for contact with the armature on the down-stroke, a sieve suspended from the core within the lower end of the shell, a spring arm above the magnet inthe path of the core, a normally closed make and break device operated by the spring arm for controlling the magnet, means on the core for engaging the spring arm for opening the make and break device on the up-stroke of the core and a leaf spring connected at its center to the sieve and having its ends engaged under the bottom of the shell for normally urging the armature against said stop. y

ALBERT C. WILCOX. 

